Re: migration thread and active_load_balance

["Dan Upton" <upton.dan.linux@gmail.com>]

>  >
>  > Anyway, like I said, I've spent several days trying to understand this
>  > error by putting in printk()s galore and doing traces through the
>
>  That might be obvious, but are you aware that printks inside
>  the scheduler can lead to deadlocks? printk when the buffer
>  is full calls wake_up and that calls the scheduler. So for
>  debugging the scheduler you need some other way to get
>  the information out.
>
>  -Andi
>

Yes, I've read that printk can cause deadlocks, although I get the
deadlocks without printks as well.  Also, I found a modification on
kerneltrap (http://kerneltrap.org/mailarchive/linux-kernel/2008/1/23/595569)
that seems to a decent job of preventing deadlocks due to printk, at
least in my case (I see in the comments on that thread though that
it's not perfect).

-dan